Arrangement and method for air management of a room

ABSTRACT

An arrangement ( 1 ) for air management of a room ( 100 ) comprises ventilating means ( 10 ) for enabling exchange of air between the inside environment ( 102 ) of the room ( 100 ) and the outside environment ( 103 ) of the room ( 100 ); a stand-alone air purifier ( 20 ), which is arranged separately from the ventilating means ( 10 ), and which is adapted to remove pollutants from the air in the inside environment ( 102 ) of the room ( 100 ); and a control system ( 30, 31, 32 ), which is in communication with both the ventilating means ( 10 ) and the air purifier ( 20 ), and which is adapted to control operation of the ventilating means ( 10 ) and the air purifier ( 20 ) in dependence of air quality data relating to the inside environment ( 102 ) of the room and the outside environment ( 103 ) of the room, the control system ( 30,31,32 ) being configured to control the ventilating means ( 10 ) and the air purifier ( 20 ) differently depending on whether the air quality data relating to the outside environment of the room ( 100 ) is above or below a predetermined reference. Operation of the arrangement ( 1 ) is aimed at optimizing indoor air quality and minimizing energy consumption.

FIELD OF THE INVENTION

The invention relates to an arrangement and a method for air managementof a room.

BACKGROUND OF THE INVENTION

Indoor air quality is an important issue which is closely related tohuman health and comfort. Pollution of indoor air constitutes asignificant risk factor for various health problems in view of the factthat many people spend most of their time, for example, more than 90% oftheir time, indoors. In general, air pollutants can be one or more ofparticle pollutants, gas pollutants and microorganisms.

Many buildings are equipped with a so-called HVAC system, i.e. aHeating, Ventilation and Air Conditioning system, for providing thermalcomfort and acceptable indoor air quality. However, in somesurroundings, particularly metropolitan cities, outdoor air pollutioncan be extremely severe, and it has been found that in suchsurroundings, the current HVAC systems are not capable of performingfiltration of all particles to a sufficient extent, wherein the systemsare particularly not effective in removing relatively small particlesfrom the input air. Furthermore, most HVAC systems are not capable ofremoving various gas pollutants such as formaldehyde and other VOCs(volatile organic compounds) from the indoor air, because the filtersused in those systems are not suitable for doing so. Another shortcomingof HVAC systems is that the systems consume a lot of energy, especiallywhen the systems are continually switched on for maintaining the airquality, which is often the case in practice.

In the field of managing quality of indoor air, in order to complementthe shortcomings of HVAC systems, stand-alone air purifiers have beendeveloped. An example of such an air purifier is known from WO2012/066453 A1. Stand-alone air purifiers are to be placed inside a roomand are very useful to people living in highly polluted cities, as theyhelp a great deal in removing various kinds of pollution from indoorair. Operation of a stand-alone air purifier requires considerably lesspower than operation of a HVAC system. Also, a stand-alone air purifieris capable of removing both large particles and small particles from theair, due to the fact that the fan which is part of the air purifier andwhich serves for forcing air to flow through the air purifier ispowerful enough to enable the application of a high efficiency filter inthe air purifier. Another advantage of the stand-alone air purifierresides in the fact that the air purifier can be used for removingindoor gas pollutants.

It is generally recommended to keep a room in which a stand-alone airpurifier is applied closed, so that it is possible to have good aircleaning efficiency. If a stand-alone air purifier would be operated inan open room, the indoor air would be hard to clean by means of the airpurifier as the source strength would be too high. However, operating astand-alone air purifier in a closed room involves an increase of thecarbon dioxide level in the room in case one or more human beings arepresent in the room. For example, if two human beings are present in aclosed room of 50 m³, carbon dioxide will accumulate in the room and thecarbon dioxide level rises up over 1,000 ppm in half an hour. Hence, thecarbon dioxide level can become too high in a relatively short period oftime, wherein it is no longer possible to comply with national and/orglobal standards, which are often based on a value of 1,000 ppm as athreshold.

A stand-alone air purifier is not capable of removing carbon dioxidefrom air. Therefore, a room in which such an air purifier is presentneeds to be ventilated, at least from time to time. In general, assumingthat the room has windows, ventilation can be realized by opening awindow, but this may worsen the indoor air quality if the outdoorquality is very bad. It cannot be left up to a user to determine theright time to open the window and to determine an appropriate durationof the ventilation action.

It is known from JPH11201511 to provide an air cleaning systemcomprising a a blower for circulating and filtering air in a room and aventilator for introducing outside air into the room. The ventilator isactivated to introduce outside air into the room when a gas detectordetects that the gas level in the room has exceeded a prescribedreference range.

SUMMARY OF THE INVENTION

It is an object of the invention to alleviate the dilemma of the need ofgood indoor quality on the one hand and the need of ventilation on theother hand. In view thereof, according to the invention, an arrangementfor air management of a room is provided, which comprises ventilatingmeans for enabling exchange of air between the inside environment of theroom and the outside environment of the room; a stand-alone airpurifier, which is arranged separately from the ventilating means, andwhich is adapted to remove pollutants from the air in the insideenvironment of the room; and a control system, which is in communicationwith both the ventilating means and the air purifier, and which isadapted to control operation of the ventilating means and the airpurifier in dependence of air quality data relating to the insideenvironment of the room and the outside environment of the room, thecontrol system being configured to control the ventilating means and theair purifier differently depending on whether the air quality datarelating to the outside environment of the room is above or below apredetermined reference. Preferably, the control system is adapted toprocess air quality data relating to both the inside environment of theroom and the outside environment of the room.

In the context of the invention, indications like “inside environment”and “indoor” should be understood such as to be related to the air whichis present inside the room, whereas indications like “outsideenvironment” and “outdoor” should be understood such as to be related tothe air which is present outside the room and which can be let in to theroom by means of the ventilating means, which in most cases is air fromthe open air which is present outside the building of which the room ispart.

On the basis of the invention, it is possible to realize optimaloperation of an arrangement comprising both ventilating means and astand-alone air purifier, so that the indoor air quality is continuallyat the best possible level and energy consumption can be at a minimum.Also, the controlling algorithms underlying the functioning of thecontrol system can be chosen such as to take a predetermined thresholdin respect of the carbon dioxide level in the room into account. Thus,the invention provides a way of avoiding a situation in which the carbondioxide level in the room can become dangerously high as a result oflong term operation of the stand-alone air purifier, avoiding asituation in which energy is wasted, and avoiding a situation in whichair cleaning only takes place at a low rate.

As mentioned in the foregoing, the arrangement according to theinvention comprises three main components, namely ventilating means, astand-alone air purifier and a control system. It is practical for theventilating means to be installed on the wall of the room, or to befixed on a window or air conditioner as may be present in the room. Theventilating means may comprise a bi-directional fan, a set of fans,wherein one fan serves for discharging air from the room and another fanserves for supplying air to the room, automatically controlled windowsor any other mechanical structure which may have a function inexchanging air between the inside environment of the room and theoutside environment of the room, for discharging dirty air from the roomand introducing fresh air to the room. The main function of thestand-alone air purifier is cleaning dirty indoor air. In particular,the air purifier may be adapted to remove at least one of gas pollutantsand particle pollutants from the indoor air. Ideally, the air flow of atleast one of the ventilating means and the air purifier can be adjusted.

The control system provides for communication between the ventilatingmeans and the air purifier, so that the operation of these components ofthe arrangement according to the invention can be adapted to each otherin order to obtain the best possible air cleaning results at minimumpower consumption. Control of the ventilating means and the air purifierincludes determining when the ventilating means and the air purifiershould be switched on and off, and may also include setting a rate ofthe air flow, for example. In any case, the control system is adapted touse both air quality data relating to at least one of the insideenvironment of the room and the outside environment of the room. The airquality data may be collected from suitable sensing means and/or ageneral data source, wherein the latter is especially applicable to airquality data relating to the outside environment of the room. Ingeneral, the data may be obtained through a data collector, which may bea sensor situated at any appropriate position inside the room and/or awebsite data collector. In a practical embodiment of the arrangementaccording to the invention, a suitable controller may be applied, whichis situated on or near the ventilating means, wherein the controller isarranged to receive information from a sensor situated on or near theventilating means for detecting carbon dioxide, particles or gaspollutants, and also from a data collector which is adapted to collectdata from an official website regarding actual outdoor air quality.Communication between the controller and at least one of the ventilatingmeans and the air purifier may take place in a wireless fashion. In anycase, a suitable controller is a controller which is adapted to followcertain algorithms which are aimed at realizing operation of theventilating means and the air purifier in such a way that the indoor airquality is always at its best under the given circumstances and waste ofenergy is avoided.

For the sake of completeness, it is noted that it is preferred for thecontrol system to be capable to automatically run a program. However,that does not alter the fact that the invention also covers a situationin which the operation of the control system can be set by a user, i.e.a situation in which the arrangement according to the inventioncomprises a user interface and in which a user can determine the statusof the ventilating means and the air purifier through the userinterface, assuming that the user does not take arbitrary action, buttakes into account actual aspects of the air quality, indoor and/oroutdoor. In this text, the most practical option of having automatic airmanagement of a room is taken as a starting point.

In the following, various options in respect of the control system willbe mentioned and elucidated.

In the first place, the control system may be adapted to compare airquality data relating to the inside environment of the room topredetermined reference data. For example, the control system may beadapted to compare an actual level of formaldehyde of the indoor air, ascan be detected by means of a suitable sensor, to a maximum allowablelevel. Starting with such comparison and depending on the outcome of thecomparison, the control system is capable of determining suitablecontrol of the operation of the ventilating means and the air purifier.In case it is found that the indoor air quality is equal to or betterthan an acceptable standard, there is no need for operating theventilating means and the air purifier, so that they can be kept in aswitched off mode, whereby energy can be saved. Hence, it isadvantageous for the control system to be adapted to set an inactivestatus of both the ventilating means and the air purifier in case it isfound that the air quality of the inside environment of the room isequal to or better than the predetermined reference. In case it is foundthat the indoor air quality is worse than an acceptable standard,control of the operation of the ventilating means and the air purifieris aimed at improving the indoor air quality. Hence, it is advantageousfor the control system to be adapted to run a program for activating atleast one of the ventilating means and the air purifier in case it isfound that the air quality of the inside environment of the room isworse than the predetermined reference.

In case it is found that the air quality of the inside environment ofthe room is worse than the predetermined reference, it is practical ifthe control system is furthermore adapted to compare air quality datarelating to the outside environment of the room to predeterminedreference data. If the outdoor air quality is good enough, it is noproblem to operate either one of the ventilating means and the airpurifier. However, if the outdoor air quality is bad, an optimum has tobe found in respect of two conflicting requirements, namely therequirement to have clean indoor air and the requirement to prevent thecarbon dioxide level of the indoor air from rising to an unacceptablevalue.

The control system is adapted to alternate an active status of theventilating means with an active status of the air purifier in case itis found that the air quality of the outside environment of the room isequal to or better than a predetermined reference. There is no need foroperating the ventilating means and the air purifier at the same time,so that energy may be saved. When the air purifier is operated, it isachieved that the indoor air quality is improved. When the ventilatingmeans are operated, carbon dioxide which has accumulated in the roomduring operation of the air purifier can be discharged from the room.After allowing for exchange between indoor air and outdoor air throughthe ventilating means, the air purifier may be switched on again.

The alternating operation of the ventilating means and the air purifiercan be repeated over and over again. In the process, it is practical tomake a comparison between indoor air quality and outdoor air quality inorder to determine whether it is best to operate the ventilating means,or to operate the air purifier. Hence, it is advantageous for thecontrol system to be adapted to make a comparison between air qualitydata relating to the inside environment of the room and air quality datarelating to the outside environment of the room, to set an active statusof the ventilating means and an inactive status of the air purifier incase it is found that the air quality of the outside environment of theroom is better than the air quality of the inside environment of theroom, and to set an inactive status of the ventilating means and anactive status of the air purifier in case it is found that the airquality of the outside environment of the room is worse than the airquality of the inside environment of the room.

According to an alternative, the control system may be adapted to run atime counter program for controlling the duration of the operation ofthe ventilating means and the air purifier, respectively. In thatrespect, it is advantageous if the arrangement comprises a userinterface for enabling a user to supply the control system withinformation regarding characteristics of the room, wherein the controlsystem is adapted to determine the duration of the operation of theventilating means and the air purifier, respectively, on the basis ofthe information. In this way, the duration of the operation of theventilating means and the air purifier, respectively, can be chosen suchas to be optimal in view of the characteristics of the room, whichinclude the size of the room and the number of people present in theroom.

According to another alternative, the arrangement comprises a flow meterfor measuring the ventilated air amount, wherein the control system isadapted to stop the operation of the ventilating means as soon as it isfound that the ventilated air amount has reached a predeterminedreference level. Also in that case, it is advantageous if thearrangement comprises a user interface for enabling a user to supply thecontrol system with information regarding characteristics of the room.The information may then be used by the control system for determiningthe reference level of the ventilated air amount.

The above options in respect of the control system are related to thesituation in which a comparison of the outdoor air quality and apredetermined reference shows that the outdoor quality is equal to orbetter than the reference. Preferably, the control system is furthermoreadapted to set an inactive status of the ventilating means and an activestatus of the air purifier in case it is found that the air quality ofthe outside environment of the room is worse than the predeterminedreference. In that way, a situation in which air of bad quality issupplied to the room is avoided, while the air purifier is used forimproving the indoor air quality. However, in order to prevent thecarbon dioxide level in the room from getting too high, it isadvantageous if the arrangement comprises sensing means for sensing thecarbon dioxide level in the room, and if the control system is adaptedto change the inactive status of the ventilating means to an activestatus as long as it is found that the carbon dioxide level in the roomis higher than a predetermined reference. In that way, the room isventilated to a minimum extent, just enough for keeping the carbondioxide level in the room at an acceptable value.

It is noted that the air quality data relating to the inside environmentof the room may comprise at least one of carbon dioxide level data,particles level data and gas pollutants level data, and that the airquality data relating to the outside environment of the room maycomprise at least one of particles level data and gas pollutants leveldata. Other types of air quality data are also feasible in respect ofthe indoor air quality and/or the outdoor air quality. Air quality datarelating to the outside environment of the room may be obtained on thebasis of detection, but it is also possible to retrieve such data from ageneral data source such as the Internet.

According to an option existing within the framework of the invention,the flow rate of at least one of the ventilating means and the airpurifier is adjustable, wherein the control system is adapted to set theflow rate of the at least one of the ventilating means and the airpurifier. Consequently, the way in which the arrangement according tothe invention realizes/maintains good indoor air quality can be evenfurther optimized.

The invention relates to both an arrangement for air management of aroom and a method for air management of a room. It follows from theforegoing that the method can be defined as a method for air managementof a room which is equipped with ventilating means for enabling exchangeof air between the inside environment of the room and the outsideenvironment of the room, and a stand-alone air purifier, which isarranged separately from the ventilating means, and which is adapted toremove pollutants from the air in the inside environment of the room,wherein operation of the ventilating means and the air purifier arecontrolled in dependence of air quality data relating to the insideenvironment of the room and the outside environment of the room, theventilating means and the air purifier being controlled differentlydepending on whether air quality data relating to the outsideenvironment of the room is above or below a predetermined reference.

In conformity with the options as described in the foregoing withrespect to the arrangement according to the invention, the followingoptions are applicable to the method according to the invention, whereinit is noted that the options are listed in a logical order which more orless reflects successive control steps:

the air quality data relating to the inside environment of the room arecompared to predetermined reference data;

an inactive status of both the ventilating means and the air purifier isset in case it is found that the air quality of the inside environmentof the room is equal to or better than a predetermined reference;

a program for activating at least one of the ventilating means and theair purifier is run in case it is found that the air quality of theinside environment of the room is worse than a predetermined reference;

air quality data relating to the outside environment of the room arecompared to predetermined reference data;

an active status of the ventilating means is alternated with an activestatus of the air purifier in case it is found that the air quality ofthe outside environment of the room is equal to or better than apredetermined reference;

a comparison is made between air quality data relating to the insideenvironment of the room and air quality data relating to the outsideenvironment of the room, an active status of the ventilating means andan inactive status of the air purifier are set in case it is found thatthe air quality of the outside environment of the room is better thanthe air quality of the inside environment of the room, and an inactivestatus of the ventilating means and an active status of the air purifierare set in case it is found that the air quality of the outsideenvironment of the room is worse than the air quality of the insideenvironment of the room;

an inactive status of the ventilating means and an active status of theair purifier are set in case it is found that the air quality of theoutside environment of the room is worse than a predetermined reference;and

sensing means are applied for sensing the carbon dioxide level in theroom, and the inactive status of the ventilating means is changed to anactive status as long as it is found that the carbon dioxide level inthe room is higher than a predetermined reference.

The following options as mentioned in respect of the arrangementaccording to the invention are also applicable to the method accordingto the invention:

a time counter program is run for controlling the duration of theoperation of the ventilating means and the air purifier, respectively;

the duration of the operation of the ventilating means and the airpurifier, respectively, is determined on the basis of informationsupplied by a user;

a flow meter is applied for measuring the ventilated air amount, and theoperation of the ventilating means is stopped as soon as it is foundthat the ventilated air amount has reached a predetermined referencelevel;

the air quality data relating to the inside environment of the roomcomprise at least one of carbon dioxide level data, particles level dataand gas pollutants level data, and the air quality data relating to theoutside environment of the room comprise at least one of particles leveldata and gas pollutants level data;

air quality data relating to the outside environment of the room areretrieved from a general data source; and

assuming that the flow rate of at least one of the ventilating means andthe air purifier is adjustable, the flow rate of the at least one of theventilating means and the air purifier is set.

The above-described and other aspects of the invention will be apparentfrom and elucidated with reference to the following detailed descriptionof a room which is equipped with an arrangement for air management ofthe room, comprising a ventilator, a stand-alone air purifier and acontrol system, and of various options in respect of control of theoperation of the ventilator and the air purifier.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in greater detail with reference tothe figures, in which:

FIG. 1 diagrammatically shows a room which is equipped with anarrangement for air management of the room, comprising a ventilator, astand-alone air purifier and a control system;

FIG. 2 is a flow chart which is applicable to the way in which theoperation of the ventilator and the air purifier is controlled in casethe outside air quality is good; and

FIG. 3 is a flow chart which is applicable to the way in which theoperation of the ventilator and the air purifier is controlled in casethe outside air quality is bad.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 diagrammatically shows a room 100 which is equipped with anarrangement 1 for air management of the room 100, comprising aventilator 10, a stand-alone air purifier 20 and a control system 30.The air purifier 20 is situated at an appropriate position in the room100, and can easily be replaced by a user to another position in theroom 100 if so desired. In the shown example, the ventilator 10 isinstalled on the wall 101 of the room 100, and is a bi-directional fanfor exhausting dirty air from the inside environment 102 of the room 100to the outside environment 103 of the room 100 and supplying fresh airfrom the outside environment 103 of the room 100 to the insideenvironment 102 of the room 100. The exchange of air is diagrammaticallydepicted by means of a set of two opposite arrows in FIG. 1.

The air purifier 20 serves for cleaning dirty air in the insideenvironment 102 of the room 100. Among other things, the air purifier 20comprises a fan (not shown) for forcing air to be purified to flowthrough the air purifier 20 during operation thereof. The flow of air toand from the air purifier 20 is diagrammatically depicted by means ofbent arrows in FIG. 1. In the shown example, the air purifier 20 iscapable of receiving and transmitting data in a wireless fashion,particularly data in respect of operation characteristics. Wirelesscommunication between the air purifier 20 and the control system 30 isdiagrammatically depicted by means of a dashed double-headed arrow inFIG. 1.

The control system 30 is adapted to run a control program which is aimedat having air of the best possible quality in the inside environment 102of the room 100, in any case having air which meets certain standards.In the shown example, the control system 30 comprises a controller 31and a data collector 32 which may be a sensor which can providereal-time indoor air quality data and/or software which can downloaddaily outdoor air quality data from an official website. For example,the sensor may be a carbon dioxide sensor, a particles sensor or a gaspollutants sensor. The control program serves for switching theventilator 10 and the air purifier 20 on and off at appropriate moments,taking into account the air quality data obtained from the datacollector 32. The controller 31 and the data collector 32 may beintegrated into the ventilator 10 as shown in FIG. 1, but anotherpositioning of the controller 31 and the data collector 32 is alsopossible, including a positioning on the air purifier 20.

FIGS. 2 and 3 illustrate possible aspects of the control program,wherein FIG. 2 relates to an algorithm which is applicable in case theoutdoor air quality is good, and wherein FIG. 3 relates to an algorithmwhich is applicable in case the outdoor air quality is bad. In short,when the outdoor air quality is good, the ventilator 10 and the airpurifier 20 are alternately operated, and when the outdoor air qualityis bad, the ventilator 10 and the air purifier 20 are first operatedsimultaneously for a few minutes, after which only the air purifier 20is operated for putting the indoor air quality to an acceptable level.

In the following, various options in respect of the arrangement 1 forair management of the room 100 will be described. It is noted thatcombinations of the options are possible within the framework of theinvention.

According to a first option, the arrangement 1 is a sensor assistedarrangement. A sensor may be placed at either the ventilator 10, the airpurifier 20 or another appropriate position in the room 100 forperforming timely measurements of the indoor air quality. The ventilator10 and the air purifier 20 will be alternately operated according to thesensor data. It is possible to use both a gas sensor and a particlesensor. In the following, by way of example, it will be assumed that thearrangement 1 for air management of the room 100 comprises aformaldehyde sensor and a carbon dioxide sensor.

The formaldehyde sensor is installed on the air purifier 20. When it isfound that the formaldehyde concentration is two/three times higher thana reference value (e.g. a national standard), the air purifier 20 isswitched on and the ventilator 10 is kept in an inactive status. Afterthe air purifier 20 has been running for a while, the formaldehydesensor will collect new data. If it is found that the formaldehydeconcentration is lower than the reference value, the air purifier 20will be put to the inactive status and the ventilator 10 will be put tothe active status for about three minutes in order to supply fresh airfrom the outside environment 103 of the room 100 to the insideenvironment 102 of the room 100. When it is found that the formaldehydeconcentration is much higher than the reference value, for example,four/five times higher, the ventilator 10 is switched on for tenminutes, including five minutes of exhaust of air from the insideenvironment 102 of the room 100 to the outside environment 103 of theroom 100, followed by five minutes of supply of fresh air from theoutside environment 103 of the room 100 to the inside environment 102 ofthe room 100. When the operation of the ventilator 10 is stopped, thesensor data are interpreted and the air purifier 20 is switched on inorder to decrease the formaldehyde concentration. After the air purifier20 has been running for a certain time, for example, half an hour to onehour, the operation of the air purifier 20 is stopped and the ventilator10 is restarted for ten minutes. The running time of the ventilator 10and the air purifier 20 can be adjustable according to both indoor airquality and outdoor air quality.

The carbon dioxide sensor can be installed on the ventilator 10, andserves for indicating the running time of the ventilator 10 and the airpurifier 20. When the carbon dioxide sensor detects that the carbondioxide level is higher than a predetermined reference value, forexample, a value of 1,600 ppm while the air purifier 20 is in the activestatus, the operation of the air purifier 20 is stopped and theventilator 10 is put to the active status in order to have air exchangefor a few minutes until the carbon dioxide level is at a lower value,for example, a value of 500 ppm. As long as the carbon dioxide levelmeasures in the inside environment 102 of the room 100 is lower than1,600 ppm while the air purifier 20 is in the active status, theventilator 10 is kept in the inactive status.

According to a second option, the arrangement 1 for air management ofthe room 100 is a big data assisted arrangement. Information about theoutdoor air quality can be obtained from an official website by asuitable data collector at any position where the Internet isaccessible. In that case, the data collector could be installed on oneof the ventilator 10, the air purifier 20 and the control system 30, orat another appropriate position in the room 100. If the outdoor qualityis bad, the ventilator 10 will be kept in the inactive status, while theair purifier 20 will be kept in the active status. After the airpurifier 20 has been running for a certain time, for example, one houror two hours, the ventilator 10 will be put to the active state for afew minutes in order to keep the carbon dioxide concentration at theacceptable level. Subsequently, ventilation will be stopped and the airpurifier 20 will be kept in the active status. If the outdoor airquality is good, the ventilator 10 will start air exchange without theair purifier 20 being in the active status as well.

According to a third option, the arrangement 1 for air management of theroom 100 is a time counter assisted arrangement, wherein a time counterprogram is used to control the duration of ventilation and airpurification. In particular, the time counter program may be used forsetting the time interval of alternating ventilation and airpurification. For example, ventilation can be performed during fiveminutes, each time after air purification has taken place during onehour. A predetermined relation may be used for determining whichduration of ventilation and air purification is appropriate for acertain size of the room 100 and a certain amount of people present inthe room 100. After the ventilator 10 has been operated during a certaintime which is appropriate in view of room size and number of peoplepresent in the room 100, the ventilator 10 will be put to the inactivecondition and the air purifier 20 will automatically be switched on.After a certain time, the air purifier 20 will be switched off and theventilator 10 will be switched on again, which is advantageous forbringing the carbon dioxide level in the room 100 down, which has becomehigher and higher in the meantime due to the presence of people in theroom 100 and the room 100 being kept closed.

According to a fourth option, the arrangement 1 for air management ofthe room 100 is a flow meter assisted arrangement. A flow meter can beused for measuring the ventilated air amount and for assisting thecontrol system 30 in determining the time interval of alternating theoperation of the ventilator 10 and the air purifier 20. After the airpurifier 20 has continuously been in the active status for one hour,while the room 100 has been kept closed, the ventilator 10 will be putto the active status in order to reduce the carbon dioxide level to anacceptable value. The flow meter on the ventilator 10 is used fordetermining when the ventilation can be stopped, while the flow rate isadjustable according to the room size. In general, it will be practicaland sufficient to exchange the air in the inside environment 102 of theroom 100 with air from the outside environment 103 of the room 100 onceper hour.

It will be clear to a person skilled in the art that the scope of theinvention is not limited to the examples discussed in the foregoing, butthat several amendments and modifications thereof are possible withoutdeviating from the scope of the invention as defined in the attachedclaims. While the invention has been illustrated and described in detailin the figures and the description, such illustration and descriptionare to be considered illustrative or exemplary only, and notrestrictive. The invention is not limited to the disclosed embodiments.

Variations to the disclosed embodiments can be understood and effectedby a person skilled in the art in practicing the claimed invention, froma study of the figures, the description and the attached claims. In theclaims, the word “comprising” does not exclude other steps or elements,and the indefinite article “a” or “an” does not exclude a plurality. Themere fact that certain measures are recited in mutually differentdependent claims does not indicate that a combination of these measurescannot be used to advantage. For example, the fact that the flow rate ofat least one of the ventilating means and the air purifier may beadjustable, wherein the control system is adapted to set the flow rateof the at least one of the ventilating means and the air purifier, isnot only applicable to the main concept of the invention as reflected inclaim 1, but may very well be combined with one or more further aspectsof the invention. Any reference signs in the claims should not beconstrued as limiting the scope of the invention.

1. Arrangement for air management of a room comprising ventilating meansfor enabling exchange of air between the inside environment of the roomand the outside environment of the room; a stand-alone air purifier,which is arranged separately from the ventilating means and which isadapted to remove pollutants from the air in the inside environment ofthe room; and a control system, which is in communication with both theventilating means and the air purifier, and which is adapted to controloperation of the ventilating means and the air purifier in dependence ofair quality data relating to the inside environment of the room and theoutside environment of the room, the control system being configured tocontrol the ventilating means and the air purifier differently dependingon whether the air quality data relating to the outside environment isabove or below a predetermined reference.
 2. Arrangement according toclaim 1, wherein the control system is adapted to compare air qualitydata relating to the inside environment of the room to predeterminedreference data.
 3. Arrangement according to claim 2, wherein the controlsystem is adapted to set an inactive status of both the ventilatingmeans and the air purifier in case it is found that the air quality ofthe inside environment of the room is equal to or better than apredetermined reference.
 4. Arrangement according to claim 2, whereinthe control system is adapted to run a program for activating at leastone of the ventilating means and the air purifier in case it is foundthat the air quality of the inside environment of the room is worse thana predetermined reference.
 5. Arrangement according to claim 4, whereinthe control system is adapted to compare air quality data relating tothe outside environment of the room to predetermined reference data. 6.Arrangement according to claim 5, wherein the control system is adaptedto alternate an active status of the ventilating means with an activestatus of the air purifier in case it is found that the air quality ofthe outside environment of the room is equal to or better than apredetermined reference.
 7. Arrangement according to claim 6, whereinthe control system is adapted to make a comparison between air qualitydata relating to the inside environment of the room and air quality datarelating to the outside environment of the room, to set an active statusof the ventilating means and an inactive status of the air purifier incase it is found that the air quality of the outside environment of theroom is better than the air quality of the inside environment of theroom, and to set an inactive status of the ventilating means and anactive status of the air purifier in case it is found that the airquality of the outside environment of the room is worse than the airquality of the inside environment of the room.
 8. Arrangement accordingto claim 6, wherein the control system is adapted to run a time counterprogram for controlling the duration of the operation of the ventilatingmeans and the air purifier, respectively.
 9. Arrangement according toclaim 8, comprising a user interface for enabling a user to supply thecontrol system with information regarding characteristics of the room,wherein the control system is adapted to determine the duration of theoperation of the ventilating means and the air purifier, respectively,on the basis of the information.
 10. Arrangement according to claim 6,comprising a flow meter for measuring the ventilated air amount, whereinthe control system is adapted to stop the operation of the ventilatingmeans as soon as it is found that the ventilated air amount has reacheda predetermined reference level.
 11. Arrangement according to claim 5,wherein the control system is adapted to set an inactive status of theventilating means and an active status of the air purifier in case it isfound that the air quality of the outside environment of the room isworse than said predetermined reference.
 12. Arrangement according toclaim 11, comprising sensing means for sensing the carbon dioxide levelin the room, wherein the control system is adapted to change theinactive status of the ventilating means to an active status as long asit is found that the carbon dioxide level in the room is higher than apredetermined reference.
 13. Arrangement according to claim 1, whereinthe air quality data relating to the inside environment of the roomcomprise at least one of carbon dioxide level data, particles level dataand gas pollutants level data, and wherein the air quality data relatingto the outside environment of the room comprise at least one ofparticles level data and gas pollutants level data.
 14. Arrangementaccording to claim 1, wherein the control system is adapted to retrieveair quality data relating to the outside environment of the room from ageneral data source.
 15. Method for air management of a room which isequipped with ventilating means for enabling exchange of air between theinside environment of the room and the outside environment of the room,and a stand-alone air purifier, which is arranged separately from theventilating means, and which is adapted to remove pollutants from theair in the inside environment of the room, wherein operation of theventilating means are controlled in dependence of air quality datarelating to the inside environment of the room and the outsideenvironment of the room, the ventilating means and the air purifierbeing controlled differently depending on whether air quality datarelating to the outside environment of the room is above or below apredetermined reference.